Autonomous and semi-autonomous vehicles are configured for unmanned operation. That is, autonomous and semi-autonomous vehicles are configured to move from one location to another, without a human driver positioned in the vehicle. One or more humans may be positioned in the vehicle but may not be providing driving input, such as controlling steering, braking acceleration and so on.
An autonomous vehicle is a vehicle that is configured to navigate, steer, accelerate and decelerate autonomously (without any human driver being positioned in or outside the vehicle that is operating the vehicle).
A semi-autonomous vehicle is a vehicle that is configured to navigate, steer, accelerate and/or decelerate, without any human driver being present in the vehicle that is operating the vehicle, in response to instructions received from a remote location (for example, wirelessly). An autonomous vehicle might be operated semi-autonomously, for instance, if it no longer becomes possible for the vehicle to operate autonomously for some reason.
A semi-autonomous vehicle may also be a vehicle that is driven by a human in the vehicle but may take control of itself for the purpose of safety or convenience. For example, the vehicle may control itself to automatically park and so on.